Inclosed-arc lamp.



n Lw w v im PATENTED AUG. 2, 1904.

OfN. WISWELL. INGLOSBD ARG LAMP.

APPLcATIoN FILED MAY 4. 139s.

N0 MODEL.

(((lClClOlQlDln) Wbnsses.

NTTE STATES Patented August 2, 1904.

PATENT OEEICE,

OZRO NEVVCOME WISVVELL, OF LYNN, MASSACIIUSFITS, ASSNNOR TO THE GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

INCLOSEDARC LAMP.

SPECIFICATION forming part of Letters Patent No.. 766,787, dated August 2, 1904.

Application filed May 4. 1899. Serial No. 715,507. (No model.)

To all whom t nto/y concern:

Be it known that I, Ozno NEwcoMe Wis- WELL, a citizen of the United States, residing at Lynn. in the county of Essex andState of Massachusetts, have invented certain new and useful Improvements in Inclosed-Arc Lamps, of which the following is a specification.

1With electric-arc lamps having a small inclosing chamber around the arc it is customary to provide a cover for the inclosure which is designed to exclude as much oxygen from the are as possible. This is done in order to prolong the life of the carbons.

In the practical construction of arc-lamps of the inclosed type it has been impracticable to make a lit between the carbon and the cap and between the cap and the inclosure which is good enough to exclude all of the oxygen from the inclosure after the lamp has started into operation, although such results are obtained as will greatly increase the carbon life. This failure is partly due to inaccuracies in the carbons and partly to inaccuracies in the cap and inclosure. In the ordinary burning of the lamp the upper carbon pumps up and down more or less, and by its action either eXpels a certain amount of inert gas from the inclosure or sucks into the inclosure a certain amount of oxygen. So long as a body of earbon gas is constantly maintained in the inclosure the carbon life is greatly prolonged; but as soon as oxygen is admitted the carbon life correspondingly decreases. I have discovered that if a suitable chamber is provided into which the inert gas is forced instead of into the surrounding atmosphere the carbon life can be materially increased. By this construction when the distance between the carbons is decreascdfrom any cause the amount of inert gas which is displaced by the moving' carbon or carbons is forced into the chamber and remains until the carbons are again separated, when it is returned to the inclosure, due to the pumping action of the moving carbon or carbons. Of course some gas may escape during the time that this action takes place; but the main body of gas acts in the manner described` he chamber may be of any desired character, eitherstraight or irtrance of oxygen.

regular; but preferably it should be of greater capacity than would suffice to contain the dis placed gas or combination of gases. When the chamber is of the proper size, no appre ciable amount of oxygen will be admitted to the inclosure even though the carbons move over their entire range. In other words, a chamber of varying capacity is provided into which the gas enters or is withdrawn, the eX- tent of movement of the carbon in no way affecting the principle of operation.

I do notwish to be understood as limiting myself to the use of a chamber the capacity of which is greater than that necessary to receive the gas displaced by the moving carbon or `carbons, since excellent results can be obtained if the chamber is more limited in capacity.

In the accompanying drawings, which illustrate an embodiment of my invention, Figure 2 is a side elevation of a gas-cap. Fig. 3 is a plan view of the same with the cover removed. Fig. 4 is a cross-section ofl the cap, taken on line 3 3 of Fig. 3. Fig. 5 is a plan view of a slightly-modified cap. Fig. 6 is a cross-section of the same. Fig. l shows a gas-cap in cross-section with a simple form of gas-chain ber, and Fig. 7 is another modilied form.

Referring to Fig. l, A represents an arcinclosing cylinder of any desired construction, and mounted on the top thereof is a gascap B. The cap is provided, with a central opening to permit the passage of the upper carbon C. The carbon and opening are so arranged that the carbon may move freely in a vertical direction. Surrounding the central opening' and concentric therewith are chambers D and D', in -which whirls of gas or air are created when the carbon C moves up and down and prevent the free exchangeof gas and air in the inclosure. Surrounding the outside of the cap is a deep groove E, forming a chamber which acts to prevent the free exit of gas from the cylinder or the en- Mounted in the cap and communicating with the chamber D is a tube F, into which the inert gas from the inclosure passes when the carbons are made to approach and from which a supply of inert gas is remay be adopted, if desired. Assuming that the carbons C and C are half-inch carbons and that the normal separation is from a half to live-eighths of an inch, then the capacity ofl the auxiliary gas chamber or tube F should be great enough to receive all of the gas forced out of the inclosure A, with ,something to spare when the carbons come together. For example, the dotted line f indicates roughly the point to which the inert gas would be forced if the carbons C and C were made to strike. The auxiliary chamber should be so arranged that it offers very little resistance to the passage of the gas from the inclosure. In the present instance the tube F communi- Cates with the concentric chamber D'; but it could be connected with the chamber D, when it would o'er slightly more resistance to the passage of the gas, or a single chamber could be substituted for thosev shown and the tube connected therewith` or the tube could enter the inclosure directly, as shown in Fig. 7. Instead of utilizing a tube, as shown, when the cap is held stationary and the inclosure A forced up against it the side tubes which support the yoke and lower-carbon holder may be employed and a suitable connection provided between the inclosure and the side tube or tubes. Regarding the action of this auxiliary chamber, the chambers D and D/ and the chamber formed by the groove E must not be considered as a part thereof, for they act to check the passage of gas and air, whereas the auxiliary chamber aims to present a comparatively free receptacle for the gas. In the sameway that the inert gas is prevented from escaping when the carbons approach, so the air is prevented from entering the inclosure when the carbons separate, for the action of the carbons separating will suck or pump back the gas previously expelled into the auxiliary chamber.

Referring to Figs. 2, 3, and 4, I have shown a slight modification of the lcap in which the auxiliary chamber F is made in the form of a spiral and lies in a horizontal plane. This arrangement is better than the one previously described, since the gas has no tendency to move when the gas in one portion of the chamber is slightly heavier than that in another portion. As before, the cap is provided with a central carbon-opening and two concentric chambers D and D surrounding the opening to check the free entrance of air and the exit of gas around the carbon. In addition to these chambers is a third and large chamber D2, located at the bottom, where the gas can enter with comparative freedom. This chamber communicates by a vertical hole D3 with the spiral auxiliary chamber F. The chamber is formed by a spiral groove on the top of the cap and a cover H, which lits over the groove and is secured in place by screws. The action of this cap is the same as the one shown in Fig. l except that the gases have no selfmoving tendency due to difference in weight. This cap is more desirable from a commercial point of view, since it occupies less space, and where the tendency is toward short lamps, as it is at the present day, this is an important item.

In Figs. 5 and 6 I have shown a slight modification of the cap previously described. The essential difference lies in the fact that the auxiliary chamber F is not made in the form of a spiral, but consists of two communicating chambers Fand F. The chambers, as shown, are concentric and are formed by grooving the top of the cap and securing a cover to the cap by screws. For convenience I have spoken of the chambers F and F; but these constitute, in effect, a single chamber. The object in placing the opening F2 at the opposite side of the cap from the opening F3, which communicates with the atmosphere, is to provide a longer path for the gas. Thereis a slight difference, however, in the construction of the auxiliary chamber from those previously described. In all the previous instances the gas and air have had but a'single path to follow, whereas they now have two paths in multiple with each other, as is clearly shown by the arrows. In placing' my attachment on electric-arc lamps it is unnecessary to make special provisions for rendering the inclosure airtight. So long as the resistance of the auxiliary chamber to the passage of gas is low the gas will enter into the chamber in preference to taking the high-resistance leaks.

It will be seen that in all the types of construction employed the gaseous arc products are provided with a long and comparatively easy path of discharge and which the entering air must traverse before reaching the inclosure, and as a result the pumping action of the inclosed gases due to the feeding of the carbons, as well as to the liuctuations in the arc, will lind relief through this easy path in preference to the other path, including the narrow opening around the electrode.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

l. An arc-inclosure provided with an opening for transit of a movable electrode and a relatively easier path of discharge for the arcgases compared with that of the feed-openingv through a reservoir of inert gas open to the atmosphere and the arc inclosure, respectively.

2. A n arc-inclosure provided with a path of discharge for the arc-gases independent of the .feed-opening, said path being open to the atmosphere and to the arc-inclosure through a long body of inert gas.

3. A gas-cap for inclosed-arc lamps, comprising a cover having a gas-chamber into IOO 'reef/e7 which the gas from the inclosure freely enters and withdraws by a different path than the :feed-opening, as the condition or the amount ol gas wit-hin the inclosure changes.

t. A gas-cap for an inelosed-arc lamp comprising a cover for closing the opening of a globe and a gas-chamber communicating with the globe at one point and with the atmosphere at a point independent ot' the feed-opening, the arrangement being such that the gas from the globe is free to enter the chamber and to withdraw without permitting the entrance o'f oxygen when the carbon electrodes move.

5. In an electric-arc lamp the combination of an inclosure for the arc, a gas-cap therefor, and a chamber connected with the inclosure which offers less resistance to the passage of gas than do the openings through which the leaks take place.

(5. A gas-cap for an inclosed-arc lamp comprising a body of metal having' a central opening for the carbon, means for restricting the exit of gas from an inclosure, and a long contracted chamber for receiving gas when a earbon pumps.

7. An arc-lamp having the arc surrounded I by a transparent or translucent substantially air-tight inclosure provided with an elongated exit-passage free from obstructions toa natural iow of the gases, whereby a normal outlow of gases and minimized diffusion or mixture with air is afforded.

8. An arc-lamp having the arc surrounded by a transparent or translucent substantially airtight inclosure, provided with an unrestricted passage leading to the atmosphere, said passage being' oit' such diameter and length as will permit the normal outliow of gases without diffusion and prevent the ingress oi the atmosphere.

9. An arc-lamp having the arc surrounded by a transparent or translucent substantially air-tigl1t inclosure provided with an elongated passage leading' from the interior of the inclosure to the atmosphere and free 'from obstructions to the natural flower' the gases and leading upward from the point of its connection with the inclosure and thence downward for the purpose set forth.

l0. An are-lamp having the arc surrounded by a transparent or translucent inclosure, a cover-plate for said inclosure, said cover-plate having an oriiice for an electrode and another oriiice for the escape of gases developed by the arc, and a bent tube connected to the second orifice and affording an unrestricted passage forthe said gases.

ln witness whereof I have hereunto set my hand this th day of April, 1899.

OZRO NEW COME VISWELL.

Witnesses:

ALEX F. MACDONALD, DUGALD MoKILLoP. 

